My need to fire up the Lavazza caused my response at 02.23 to crosspost with your earlier update, fluffy.
I'm unsurprised that the paramedics determined that your friend was not in need of hospitalisation and if some of the armchair doctors here did a stint on A&E they'd rapidly learn not to make a large screen technicolour drama out of a very minor crisis.
I suggest you have a very serious talk with your friend later today about the effect tonight's events have had on you, and advise her to seek counselling via her GP before she manages to do away with herself simply because she craved the blessed relief that sleep can bring when life's problems get too much for us.
Remind her that if she pops her clogs prior to the Absolute being decreed, there'll only be one winner and she needn't think that she'll be able to haunt him until it's his turn to shrug off this mortal coil. I also suggest you refer her to the Relationships board where there'll be no shortage of hands to hold hers at any hour of the day or night, and where women who've been through worse what she's contending with will provide sound advice that will see her through whatever her stbxh chucks at her.
While I'm in the business of 'suggesting', get yourself along to your own GP for a little help in the form of a short course of ads or sleeps and/or offload whatever issues have caused you to temporarily implode on what you consider to be the most appropriate board on this site.
Quite apart from your current 'fragile' state, you've had a dreadful shock that warrants being very kind to yourself until you've recovered your equilibrium - stay warm, make tasty treats for yourself or cook comfort food, eat little and often, and be sure to keep hydrated throughout the day.
I hope your friend can see how very unfair she's being/been to you but, if not, please know that in the event that you are unable to 'save' her from herself it will be because there was nothing you could have done as it was her time to go. Seriously, fluffy - when your number's up no-one on this earth has the power to recall it and no-one should beat themselves up for that fact of life, or death as the case may be.
If you find it is getting too much for you, please don't have any compunction about returning you friend's key to her as you've already gone the extra mile and you were not put on this earth to be her keeper.